Screw-type implants are well known in the art. U.S. Pat. No. 3,499,222 of L. I. Linkow et al. discloses screwtype implants which may be buried in the alveolar ridge crest bone of a patient in an edentulous region. The implant has a threaded lower portion which may be screwed into an opening created in the bone after the tissue has been displaced. A coronal portion protrudes above the bone and is used to support an artificial dental appliance, e.g. an artificial tooth or bridge.
In more recent years submergible implants have been created in which the threaded portions of the implants can be completely embedded in the bone. They may then be covered with tissue and allowed to remain in place while new bone grows around the implant and through vent holes in it. Once it is firmly anchored in new bone (3 to 6 months), the tissue is reopened and an upper post portion is screwed into the implant portion and is used to mount the artificial dental device.
It is advantageous when installing an implant portion in the patient's bone, if the implant is self-tapping in a bore created in the bone. This causes it to be anchored better. Also, it would be advantageous if the bone chips created during a self-tapping operation were deposited into the bore or opening because these chips promote faster bone growth because of their autogenous nature.
In order to align the artificial tooth or other dental devices with the other teeth of the patient, it may be necessary to have the post portion at an angle to the implant portion. This may be accomplished by bending the post portion so that its head is at an angle to the threaded shaft. This bending may be accomplished before the post is threaded into the implant portion or afterward. If the post is bent before attachment to the implant, the proper alignment is difficult to achieve. If bent after attachment, there is a danger that too much stress will be put on the implant portion and it will loosen in the bone and fail. Also bending the post may fatigue the metal of the post and cause breakage.